[NTG-context] error calling font.getfont() on certain fonts

Hans Hagen pragma at wxs.nl
Fri Mar 29 15:21:04 CET 2013


On 3/28/2013 6:41 PM, Philipp Gesang wrote:
> Hi all,
>
> I get an error when I run this code:
>
>      \ctxlua{font.getfont( font.current() )}
>
> (Complete example below.) Oddly, whether or not this fails
> depends on the font. The issue does occur with both today’s beta
> and Tex Live. The error message is
>
>      error: .../context/tex/texmf-context/tex/context/base/node-inj.lua:97: attempt to perform arithmetic on local 'factor' (a nil value)
>
> At the same time, in Plain the equivalent code works fine for all
> fonts. Bug or feature?

it's a side effect ... it looks like font.getfont operates on the table 
passed to tex and when you request it it probably fills in some data 
(like parameters) thereby overloading / wiping out existing stuff so 
after that call the data structure as context uses (and needs) it is 
messed up

add this after the definition of definers.read(specification,size,id) 
and it will probably work ok

function font.getfont(id)
     return fontdata[id] -- otherwise issues
end

(I'll add a similar overload someplace else.)

> Best regards
> Philipp
>
>
> %% working fonts:
> %\setupbodyfont[iwona]
> %\setupbodyfont[computer-modern-unicode]
> %\setupbodyfont[antykwa-poltawskiego]
> %% ... ?
>
> %% not working:
> \setupbodyfont[modern]
> %\setupbodyfont[antykwa]
> %\setupbodyfont[termes]
> %\setupbodyfont[pagella]
> %\setupbodyfont[bonum]
> %% ... ?
>
> \starttext
>    foo
>    \ctxlua{font.getfont( font.current() )}
>    bar
> \stoptext

in context you can try this:

\startluacode
     function font.getfont(id)
         return fonts.hashes.identifiers[id]
     end
\stopluacode

\starttext

   foo
   \ctxlua{inspect(font.getfont( font.current()).parameters )}
   bar
\stoptext

if you comment the function overload you see the difference

Hans


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